custom widgets

backend refactor

new: canvas widget

bump cute version in docs

Fix version

Add declarative API: computed state, fetch, inline props, and reactiv…

…e bindings

New features: state.update() for transform-in-place, cute.computed() for
derived state, cute.fetch() for async work, state-aware stylesheet(),
reactive cute.list(), two-way input binding, and inline props on layouts
and widgets. Default parameter values remove the need for trailing nils.

Updated both examples to use the new API and refreshed all docs.

add Examples

initial release